diff --git a/plugins/experimental/uri_signing/jwt.c b/plugins/experimental/uri_signing/jwt.c
index a38565c5385..69a07e3714c 100644
--- a/plugins/experimental/uri_signing/jwt.c
+++ b/plugins/experimental/uri_signing/jwt.c
@@ -97,12 +97,6 @@ unsupported_string_claim(const char *str)
   return !str;
 }
 
-bool
-unsupported_date_claim(double t)
-{
-  return isnan(t);
-}
-
 bool
 jwt_validate(struct jwt *jwt)
 {
@@ -126,8 +120,8 @@ jwt_validate(struct jwt *jwt)
     return false;
   }
 
-  if (!unsupported_date_claim(jwt->nbf)) {
-    PluginDebug("Initial JWT Failure: nbf unsupported");
+  if (now() < jwt->nbf) {
+    PluginDebug("Initial JWT Failure: nbf claim violated");
     return false;
   }